Image pickup apparatus, image pickup lens, and data writing method to image pickup lens

ABSTRACT

To enable to display a scale indicative of a reference length on a screen of a display at an accurate length even when exchanging the lens in an image pickup apparatus to any lens. 
     In a case of mounting an exchange lens ( 4 F,  4 Z) to an image pickup apparatus main body ( 3 ) and displaying an image of an object picked up by an image sensor ( 2 ) and a scale ( 5 ) indicative of a reference length in juxtaposition on a screen of a display ( 6 ), a previously measured optical magnification or an actual magnification is outputted from optical magnification outputting means ( 8 ) provided to the exchange lens ( 4 F,  4 Z) is outputted, an actual magnification on the screen of the display ( 6 ) is calculated based on the optical magnification, the size for the image sensor and the screen size, and the size of the scale on the screen is set based on the actual magnification and the reference length of the scale by a scale setting means ( 17 ).

TECHNICAL FIELD

The present invention concerns a lens exchange type image pickupapparatus having an image processing apparatus of displaying an image ofan object picked up by an image sensor and a scale indicative of areference length in juxtaposition on a display screen, and an exchangelens used therefor.

BACKGROUND ART

In the image pickup apparatus, when an object is displayed on the screenof a display, a scale is displayed in juxtaposition on the screen suchthat the size of the object can be recognized easily.

In this case, when an optical magnification of a lens is constant, itmay suffice to display a scale of a predetermined size but, in a case ofusing a variable magnification lens such as a zoom lens, it is alsonecessary to change the size of the scale in accordance with themagnification.

In such existent image pickup apparatus, it has been adapted to detectthe position of a magnification adjusting movable lens and a varifocalmovable lens used in a zoom lens, calculate the optical magnification ofthe lens based thereon, and set the size of the scale.

[Patent Document 1] JP-A No. 10-210327

However, in an image pickup apparatus of high magnification used as amicroscope, since the focus is adjusted by relative movement of a stagein the direction of the optical axis, the lens has no varifocal movablelens and since the lens of high magnification has an extremely shallowdepth of field and the object distance is primarily determined, so thatit is not necessary to detect the same.

In view of the above, it has also been proposed an image pickupapparatus of reading a positional information of a lens based on outputsignals from a driving section for a magnification adjusting movablelens, calculating the magnification and setting the scale.

[Patent Document 2] JP-A No. 2000-155268

However, since a lens includes a magnification error of about 5% in afixed focal length lens and about 10% in a zoom lens, in a case where itis intended to detect the magnification based on output signals from thedriving section for the magnification adjusting movable lens, itinevitably contains an error of about 5 to 10%.

Further, since the positional information of the magnification adjustingmovable lens is outputted from a zoom lens in any case and themagnification is detected based on the positional information in animage pickup apparatus main body, it is necessary to store data inherentto the lens necessary for converting the positional information into themagnification on the side of the image pickup apparatus.

In this case, since there is only one kind of data inherent to the zoomlens to be used in the existent image pickup apparatus not capable oflens exchange, it may suffice to merely store the data thereof.

However, in a case of using an image pickup apparatus as a microscope,it has been demanded that observation can be conducted under anappropriate magnification over a wide range of factor, for example, fromseveral to several hundreds times depending on a body to be observed(object), and the range capable of controlling the enlargingmagnification with only one zoom lens is restricted and themagnification can not be set freely.

Further, there is also a demand of using various kinds of lenses whileexchanging them such that lenses of optional optical characteristics canbe used selectively.

In this case, the demand can be satisfied by using an image pickupapparatus capable of lens exchange. However, since the data inherent tothe lens are different in a case of calculating the magnification basedon the positional information of the lens respectively upon exchange oflens, the enlarging magnification can not be calculated.

Further, in a case of a magnification fixed lens, since a magnificationcontrolling variable lens is not present, the enlarging magnificationcan not be calculated based on the positional information.

Accordingly, it has been difficult to display a scale indicative of areference length at an accurate length on a screen.

DISCLOSURE OF THE INVENTION Subject to be Solved by the Invention

In view of the above, it is a technical subject of the invention forenabling to display a scale indicative of a reference length at anaccurate length on the screen of a display even upon exchange to anylens.

Means for Solving the Subject

For solving the subject, an image pickup apparatus according to thepresent invention has a feature in a lens exchange type image pickupapparatus having an image processing apparatus of displaying an image ofan object picked up by an image sensor and a scale indicative of areference length in juxtaposition, in that an exchange lens mounted toan the image pickup apparatus main body has optical magnificationoutputting means for outputting a predetermined optical magnification,the image processing apparatus has actual magnification calculationmeans for calculating an actual magnification on a screen of a displaybased on the optical magnification, the size for the image sensor andthe size of the screen and scale setting means of setting a scale basedon the calculated actual magnification and the reference length of ascale to be displayed.

Further, an exchange lens for enlarged image pickup according to theinvention is an exchange lens for enlarged image pickup mounteddetachably to an image pickup apparatus main body having an imagesensor, characterized by the provision of optical magnificationoutputting means of outputting a previously measured opticalmagnification.

EFFECT OF THE INVENTION

According to the image pickup apparatus of the invention, since anexchange lens mounted to the image pickup apparatus main body has theoptical magnification outputting means as described in claim 1 and claim4, and since the optical magnification previously set to each lens isoutputted individually on every lens, an accurate optical magnificationcan be obtained even upon exchange of the lens.

Further, since an accurate optical magnification is measured onindividual lens before shipping of the lens and the data is stored in amemory device as described in claim 2 and claim 5, the opticalmagnification of the exchanged lens can be outputted accurately with noerror.

Then, an actual magnification on the screen of the display is calculatedbased on the magnification, and based on the size for the image sensorand the screen size, for example, by the following equation:MR=MO×D/din which

MR: actual magnification

MO: optical magnification of lens

D: screen size on display

d: size for image sensor

Then, in a case of displaying the scale of a reference length S, thelength L of the scale on the image is determined according to thefollowing equation and a scale can be displayed at an accurate length onthe screen of the display:L=MR×S

Further, in a case of a zoom lens where the exchange lens has amagnification adjusting movable lens, since a position sensor fordetecting a movable lens position or a movable portion positioncorresponding thereto, and a memory device for storing aposition-magnification conversion data of outputting an opticalmagnification in accordance with the detection position of the positionsensor based on the previously measured optical magnification areprovided as described in claim 3 and claim 6, when the opticalmagnification is controlled, an accurate optical magnification isoutputted in accordance with the detection position of the positionsensor, and the length of the scale can be accurately changed anddisplayed based thereon on real time.

BEST MODE FOR PRACTICING THE INVENTION

In this embodiment, a subject of enabling display for a scale indicativeof a reference length on a screen of a display at an accurate lengtheven upon lens exchange has been attained by outputting an opticalmagnification from the exchange lens.

FIG. 1 is an explanatory view showing a first embodiment of an imagepickup apparatus according to the invention, FIG. 2 is an explanatoryview showing a second embodiment, and FIG. 3 to FIG. 6 are flow chartsshowing data writing/reading procedures.

EMBODIMENT 1

An image pickup apparatus 1 of this embodiment includes an image pickupapparatus main body 3 having an image sensor 2, an exchange lens 4F, 4Zmounted exchangeably thereto, and an image processing apparatus 7 fordisplaying a scale 5 indicative of a reference length on a screen of adisplay 6 in juxtaposition together with an image of an object outputtedfrom the image sensor 2.

The exchange lens 4F is a fixed magnification lens having an opticalmagnification outputting means 8 for outputting a previously set opticalmagnification MO.

The optical magnification outputting means 8 has a memory device 9 forstoring a previously measured optical magnification MO. When lenses at afactor, for example, of 100× are designed and manufactured, an opticalmagnifications MO is accurately measured again on every individuallenses and when the measured optical magnification is 04.3×, 98.2×,etc., the value is stored in the memory device 9.

The exchange lens 4Z is a zoom lens using a magnification adjustingmovable lens 10 and it has a position sensor 11 for detecting theposition of the movable lens or a position of a movable portioncorresponding thereto (rotational angle of a magnification controllingring), and a memory device 12 for storing a position-magnificationconversion data of outputting an optical magnification in accordancewith the detection position of the position sensor 11 based on thepreviously measured optical magnification as the optical magnificationoutputting means 8.

In the exchange lens 4Z, since the magnification changes in accordancewith the position of the movable lens 10, when zoom lenses capable ofcontrolling the magnification, for example, from 30× to 100× aredesigned and manufactured, optical magnifications MOn and detectionpositions Pn outputted correspondingly from the position sensor 11 aremeasured at a plurality of measuring points while moving the movablelens 10 on every individual lenses 4Z, and position-magnificationconversion data of converting the detection position into the opticalmagnification based on the detection position Pn and the opticalmagnification MOn are stored in the memory device 12.

The position-magnification conversion data uses, for example, a tableformed by plotting measuring points on a graph expressing the detectionposition Pn on the axis X and the optical magnification MOn on the axisY and preparing a graph connecting them with an approximate line intodata.

Then, on every movement of the movable lens 10, the detection positionis outputted from the position sensor 11 and an optical magnification isoutputted in accordance with the detection position.

The image processing apparatus 7 has an image generating section 13 forgenerating an image from an image data for an object outputted from theimage sensor 2 of the image pickup apparatus main body 3, a scalegenerating section 14 for generating a scale 5 based on the opticalmagnification outputted from the exchange lenses 4F, 4Z, and a displayimage outputting section 15 for displaying the image generated by theimage generating section 13 and the scale 5 set by the scale generatingsection 14 in juxtaposition on the screen of the display 6.

The image processing apparatus 7 is not restricted only to a machineused exclusively herein to which the image pickup apparatus main body 3,the exchange lens 4F, 4Z, and the display 6 are connected, but it may bea general-purpose machine such as a personal computer, or it may beassembled into the image pickup apparatus main body 3.

The scale generating section 14 has an actual magnification calculationmeans 16 for calculating an actual magnification MR on the screen of thedisplay 6 and a scale setting means 17 for deciding the length on thescreen of the scale 5 indicative of the reference length.

The actual magnification calculation means 16 calculates the actualmagnification MR on the screen of the display 6 according to thefollowing equation based on the optical magnification MO outputted fromthe exchange lenses 4F, 42, the previously set size d for the imagesensor 2, and the screen size D of the display 6 to be used:MR=MO×D/d

The size d for the image sensor 2 and the screen size D are that for thecorresponding portion and, for example, in a case where the lateralwidth of the image sensor 2 and the lateral width of the image screen ofthe display 6 are corresponded, they are the lateral width thereof.

Further, the actual magnification calculating means 16 outputs acharacter data for the actual magnification MR to the display imageoutputting section 15 so that numerical value for the actualmagnification MR can be displayed on the screen.

In this case, since the size d for the image sensor 2 and the screensize D of the display 6 to be used are known, when the values arepreviously inputted, the actual magnification MR can be determined onlythe optical magnification MO outputted from the exchange lens 4F, 4Zbeing as the variant.

For example, in a case where the size for the image sensor 2 is: d=8 mmand the screen size of the display 6 is: D=356 mm, the actualmagnification MR of the image pickup apparatus 1 is represented as:MR=MO×356/8=44.5×MO

In a case where the optical magnification outputted from the exchangelens 4F, 4Z is: MO=2.2×, the actual magnification MR of an objectdisplayed on the display 6 is:MR=2.2×44.5=97.9and the character data is “×97.9”.

Further, in the scale setting means 17, when a reference length S of thescale 5 to be displayed is inputted, the length L of the scale 5 on thescreen is calculated according to the following equation:L=MR×S

For example, in a case of intending to display the scale 5 indicative ofthe reference length: S=1 mm, the length L thereof on the screen is:L=97.9×1 mm=97.9 mm

Then, the length 97.9 mm is converted into the number of pixels, and theimage data for the scale 5 of a length corresponding to the number ofthe pixels and the character data indicating the size of the referencelength S (for example “1 mm”) is outputted to the display imageoutputting section 15.

Thus, image data containing the image of an object picked up by theimage sensor 2, the scale 5 indicative of the reference length S, acharacter data for “1 mm” indicating the size of the scale 5 and thecharacter data: “×97.9” showing the actual magnification are outputtedand displayed on the screen of the display 6.

A constitutional example of the invention is as has been described aboveand the operation thereof is to be described.

At first, upon manufacturing the exchange lenses 4F, 4Z, opticalmagnification is accurately measured on every individual lens. In thefixed magnification exchange lens 4F, the optical magnification thereofis stored in the memory device 9. In the valuable magnification exchangelens 4Z, optical magnification MOn and detection position Pn aremeasured at a plurality of measuring points while moving the movablelens 10, and the data of a graph formed by connecting the measuringpoints with an approximate line based thereon is stored as theposition-magnification conversion data in the memory device 12.

Then, an optional exchange lens 4F, 4Z is mounted to the image pickupapparatus main body 3 and, when an object is picked up, an image takenby the image sensor is outputted by way of the image generating section13 of the image processing apparatus 7 to the display image outputtingsection 15.

In this case, when a fixed magnification exchange lens 4F is mounted,the optical magnification MO of the lens 4F is outputted from the memorydevice 9 of the optical magnification outputting means 8 and inputted tothe scale generating section 14 of the image processing apparatus 7.

In the scale generating section 14, an actual magnification MR on thescreen of the display 6 is calculated based on the optical magnificationMO, the size d for the image sensor 2, and the screen size D of thedisplay 6 by the actual magnification calculation means 16, the length Lof the scale S on the screen is set based on the actual magnification MRand the reference length S by the scale setting means 17, and the imagedata for the scale 5 and the character data for the reference length Sare outputted to the display image outputting section 15.

As a result, an image data for the object, an image data for the scale5, a character data for the reference length S, and a numeral data forthe actual magnification MR are outputted from the display imageoutputting section 15 to the display 6 and displayed on the screen.

Further, in a case where a magnification variable exchange lens 4Z ismounted, the position for the magnification adjusting movable lens 10 isdetected by the position sensor 11 on every movement, and the opticalmagnification is inputted based on the detection position by way of theposition-magnification converter 12 to the scale generating section 14of the image processing apparatus 7.

Then, in the same manner as described above, the data for the scale 5indicative of the reference length S is outputted to the display imageoutputting section 15.

As a result, an image data for the object, an image data for the scale5, a character data for the reference length S, and a numerical data forthe actual magnification MR are outputted from the display imageoutputting section 15 to the display 6 and displayed on the screenthereof and, since the optical magnification MO of the exchange lens 4Zis outputted and the actual magnification MR is calculated, on everycontrol for the magnification, the length of the scale 5 displayed onthe screen and the actual magnification MR are changed on real time.

As has been described above according to the invention, upon exchange toan optional exchange lens 4F, 4Z, since the previously measured accurateoptical magnification of the lens is outputted from the lens and thescale is set at the actual magnification calculated based thereon, itprovides an excellent effect capable of displaying the scale 5indicative of the reference length S at an accurate length on the screenof the display 6.

EMBODIMENT 2

In the image pickup apparatus shown in FIG. 2, an image pickup lens 24capable of controlling the magnification is mounted to an image pickupapparatus main body 23 having an image sensor 22, and an imageprocessing apparatus 27 intended to display an image of an object pickedup by the image sensor 22 and a scale 25 indicative of a referencelength in juxtaposition on a display 26 of a predetermined image screensize is provided.

The image pickup lens 24 has a position sensor 29 for detecting theposition of a magnification adjusting movable lens 28 or a position of amovable portion corresponding thereto, and carries a microcomputer 30for outputting an optical magnification MO corresponding to thedetection position by the position sensor 29 and a nominal magnificationMN.

Further, a zoom ring 31 for operating the magnification adjustingmovable lens 28 has a click mechanism to be stopped at a position for ascale marking value for actual magnification MR attached to a zoomindicator 32. For example, in a case of using a display of an assumedscreen size and in a case where the actual magnification MR changes from10× to 50×, a scale marking values N for 10×, 20×, 30×, 40× and 50× areattached to the zoom indicator 32, and the zoom ring 31 is clicked tostop at the scale position.

The microcomputer 30 has a data memory 33 for storing a magnificationdata corresponding to the detection position and a program memory 34 forstoring a program for reading/writing the data.

The data memory 33 records a position-magnification conversion table 35recording an optical magnification MO corresponding to the previouslymeasured detection position of the position sensor 29, and has a nominalmagnification outputting means 36 of outputting a nominal magnificationMN to be displayed on the display.

In the position-magnification conversion table 35, an opticalmagnification is recorded corresponding to the position data for thedetection position outputted from the position sensor 29 uponmeasurement of the optical magnification, and a positional data is setcorresponding to the click position.

Accordingly, while the optical magnification is outputted in accordancewith the position data outputted from the position sensor 29, thedetection value may sometimes vary between the case of operating thezoom ring 31 from a lower magnification side to a higher magnificationside and a case of operation from the higher magnification side to thelower magnification side due to backrush of the position sensor 29, etc.and, particularly, the length of the scale 25 changes irrespective ofalignment of the zoom ring 31 to an identical click position.

Therefore, in this embodiment, in a case where the detection positionoutputted from the position sensor 29 is within a predetermined range oferror previously set around the click position to be stopped by theclick mechanism, not an optical magnification corresponding to each ofthe positional data but an optical magnification data corresponding tothe positional data set as the click position is outputted compulsorily.

Further, due to the individual difference of individual lensmagnifications used for the image pickup lens 24 or the mechanical errorof the zoom mechanism, even when it is aligned with a predeterminedclick position (for example 20×), the actual magnification MR uponcontrol can scarcely be 20× accurately.

Further, upon picking up an image of the object, it may suffice that theactual magnification MR is reflected on the length of the scale 25 and,as a magnification value to be indicated on the image screen, a nominalmagnification representing an approximate image pickup magnification israther used generally.

Then, the nominal magnification outputting means 36 is adapted to outputa nominal magnification data MN corresponding to a scale marking value Nindicated on the zoom indicator 32 when the detection position outputtedfrom the position sensor 29 is within a predetermined range of errorpreviously set around the scale position stopped by the click mechanismas a center.

Further, the image processing apparatus 27 has an image generatingsection 37 for generating an image from the image data for an objectoutputted from the image sensor 22 of the image pickup apparatus mainbody 23, a scale generating section 38 for setting a scale based on theoptical magnification Mo outputted from the microcomputer 30 of theimage pickup lens 24 and the reference length S of the scale 25 to beindicated, and a display image outputting section 39 for generating animage to be displayed on the display 26.

The display image outputting section 39 generates images for displayingthe scale 25 set by the scale generating section 38 and the value forthe nominal magnification MN when the nominal magnification MN isoutputted from the microcomputer 30 of the image pickup lens 24 beingjuxtaposed with the image generated by the image generating section 37.

The image processing apparatus 7 is not restricted only to a machineused exclusively herein to which the image pickup apparatus main body23, the image pickup lens 24, and the display 26 are connected, but itmay be a general-purpose machine such as a personal computer, or it maybe assembled into the image pickup apparatus main body 23.

The scale generating section 38 has an actual magnification calculationmeans 40 for calculating an actual magnification MR on the screen of thedisplay 26 and a scale setting means 41 for deciding the length on thescreen of the scale 5 indicative of the reference length.

The actual magnification calculation means 40 calculates the actualmagnification MR on the screen of the display 26 based on the opticalmagnification MO outputted from the image pickup lens 24, the previouslyset size d for the image sensor 22, and the screen size D of the display26 to be used according to the following equation:MR=MO×D/d

The size d for the image sensor 22 and the screen size D are those forthe corresponding portion and, for example, in a case where the lateralwidth of the image sensor 22 and the lateral width of the image screenof the display 26 are corresponded, they are the lateral width thereof.

Further, the actual magnification calculating means 40 outputs acharacter data for the actual magnification MR to the display imageoutputting section 39 so that a numerical value for the actualmagnification MR can be displayed on the screen.

In a case of writing/reading position-magnification data to the datamemory 33, a program capable of inputting/outputting the data is storedin the program memory 34 of the microcomputer 30, the position data forthe magnification adjusting movable lens 28 is outputted uponmeasurement of the optical magnification by using the program in theprior art, the position-magnification data is measured which is thenwritten in the data memory 33, and the actual magnification can beoutputted based on the position data upon image pickup.

However, a problem has occurred in this case that the data written inthe data memory 33 should be lost or the program runs uncontrollably tooverwrite random numerical value data when an excess current flowstemporarily by connection/disconnection of a connector, or like otherexternal disturbance.

In view of the above, in this embodiment, position-magnification data iswritten/read by the following procedures so as not to cause suchtroubles.

FIG. 3 is an explanatory view showing the procedure. At step STP1, apositional data output program PRG1 only for outputting the positiondata of the magnification adjusting movable lens 28 detected by theposition sensor 29 is stored in the program memory 34, and the positiondata is outputted successively upon measurement of the opticalmagnification.

Then, at step STP2, a read/write program PRG2 capable of writing/readingthe measured optical magnification and the position data is written overthe program memory 34 and the position data and the magnification dataare written to the position-magnification conversion table 35 of thedata memory 33.

At step STP3, a read only program PRG3 capable of reading themagnification data corresponding to the position data of theposition-magnification conversion table 35 recorded in the data memory33 and not having data writing means to the data memory 33 is writtenover the program memory 34, so that optical magnification data can beoutputted upon image pickup.

FIG. 4 shows a concrete procedure of the position data outputtingprogram PRG1 used upon measurement of the optical magnification. At stepSTP11, an output signal from the position sensor 29 is put to A/Dconversion, which is outputted as a position data at step STP12 and thenit returns to step STP11.

According to the procedure, on every movement of the magnificationadjusting movable lens 28 by the operation to the zoom ring 31, theposition is detected by the position sensor 29 and the position dataPSDn is outputted.

Accordingly, when a scale, for example, is picked up, the opticalmagnification is calculated based on the actual length thereof, thelength of the scale transferred to the display 26, and the size of theimage sensor 22 and the display 6, and then an optical magnificationdata MODn corresponding to the position data PSDn may be determinedsuccessively.

FIG. 5 shows a specific example of a read/write program PRG2 used fordata writing. At step STP21, on every data input from a personalcomputer, etc. storing the previously measured position-magnificationdata, the data is written at a predetermined address in theposition-magnification conversion table 35 and then it goes to stepSTP22 at the instance the data writing has been completed.

The step STP22 is for confirmation that the optical magnification datahas been outputted properly or not based on the position data when theposition data is outputted from the position sensor 29. The value of theoptical magnification data corresponding to the positional data isoutputted when the same has been recorded whereas, in a case where thedata has not been recorded, a value calculated from the opticalmagnification data corresponding to two position data before and afterthe same is outputted.

FIG. 6 shows a specific example of a read only program PRG3 used forimage pickup. At step STP31, an optical magnification data is outputtedbased on the positional data outputted from the position sensor 29. In acase where an optical magnification data corresponding to the positiondata is recorded, the value is outputted and in a case where it is notrecorded a value is calculated from the optical magnification datacorresponding to two position data before and after thereof andoutputted.

Since the program PRG3 has no data writing command, it does not re-writethe content of the data memory 33 even how the program runsuncontrollably.

An constitutional example of this embodiment has been described aboveand the operation thereof is to be described.

At first, when the optical magnification of the valuable magnificationimage pickup lens 24 is measured, the position data outputting programPRG1 is written in the program memory 34 and, based on the opticalmagnification MRn and the detection position Pn measured at a pluralityof measuring points while moving the magnification adjusting movablelens 28, the position-magnification conversion data is prepared based onthe data for the measuring points.

Then, when a data is written in the position-magnification conversiontable 35 of the data memory 33, the position data outputting programPRG1 is eliminated by writing the read/write program PRG2 over theprogram memory 34 and, when the previously preparedposition-magnification conversion data is inputted from the personalcomputer or the like, data is written in the position-magnificationconversion table 35 by the read/write program PRG2.

When the zoom ring 31 is operated in this state, the position of themagnification adjusting movable lens 28 is detected by the positionsensor 29, and an optical magnification MO corresponding to the positiondata PSD is outputted with reference to the position-magnificationconversion table 35, to display the scale 25 of the reference length Son the display 26 by the image processing apparatus 27.

Accordingly, in a case where an image of an object attached with a scaleidentical with the reference length S is picked up, when the length ofthe scale 25 is indicated on the display 26 so as to align with thescale pitch of the object upon changing the magnification, it can beconfirmed that data has been inputted correctly.

After completion of the confirming operation, the read/write programPRG2 is eliminated by overwriting the read only program PRG3 on theprogram memory 34.

Then, when the image of an object is picked up, the image taken into theimage sensor 22 is outputted by way of the image generating section 37of the image processing apparatus 27 on the display image outputtingsection 39.

Then, when the zoom ring 31 is operated, the position of themagnification adjusting movable lens 28 is detected by the positionsensor 29, an actual magnification MR corresponding to the position dataPSD is inputted to the scale setter 38 of the image processing apparatus27 with reference to the position-magnification conversion table 35, andthe data for the scale 35 indicative of the reference length S isoutputted to the display image outputting section 39.

Further, when the zoom ring 31 is clicked to stop at the position forthe scale marking value N attached to the zoom indicator 32 (forexample, 10×, 20×, 30×, 40×, and 50×), a nominal magnification data MNcorresponding to the scale marking value N indicated on the zoomindicator 32 is always outputted even in a case where the positionsensor 29 includes backrush.

Thus, when the zoom ring 31 is clicked to stop, the scale marking valueN can always be indicated as the nominal magnification MN.

Further, in the same manner, when the zoom ring 31 is clicked to stop,since an optical magnification data corresponding to the position dataset as the click position is outputted compulsorily, a predeterminedoptical magnification MO is always outputted at the click position,which does not fluctuate by the effect of the backrush, etc.

As a result, the image data for the object, the image data for the scale25, the character data for the reference length S and, optionally, anumerical data for the nominal magnification MN are outputted by thedisplay image outputting section 39 to the display 26 and displayed onthe screen.

Then, since the optical magnification MO is updated on every control formagnification, the actual magnification MR also changes, and the lengthof the scale 25 indicated on the screen is also changed according to thecontrol for the magnification on real time.

As has been described above, in a case of using the image pickup lens 24of this embodiment, since the optical magnification MO under currentimage pickup is outputted on real time and, when the zoom ring 31 isclicked to stop, the nominal magnification therefor is outputted, thescale 25 indicative of the reference length S on the screen of thedisplay 26 can be displayed at an accurate length upon exchange to anylens and, further, a nominal magnification upon alignment to the clickposition can also be displayed.

Further, since the program written in the microcomputer 30 of the imagepickup lens 24 upon image pickup is the read only program PRG 3 and hasno data writing command, even when the program PRG3 runs uncontrollably,data in the data memory 33 is not lost, or random numerical data is notoverwritten.

INDUSTRIAL APPLICABILITY

As has been described above, according to the present invention, sincethe scale indicative of the reference length S can be displayed at anaccurate length irrespective of the kind of the image pickup lens, it issuitable to the application use for a lens exchange type image pickupapparatus used, for example, in a microscope.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory view showing a first embodiment of an imagepickup apparatus according to the present invention

FIG. 2 is an explanatory view showing a second embodiment.

FIG. 3 is a flow chart showing a data writing/reading procedure.

FIG. 4 is a flow chart for a position data outputting program.

FIG. 5 is a flow chart for a read/write program.

FIG. 6 is a flow chart of a read only program.

DESCRIPTION OF REFERENCES

-   1 image pickup apparatus-   2 image sensor-   3 image pickup apparatus main body-   4F, 4Z exchange lens-   5 scale-   6 display-   7 image processing apparatus-   8 optical magnification outputting means-   9 memory device-   10 magnification adjusting movable lens-   11 position sensor-   12 position-magnification converter-   16 actual magnification calculation means-   17 scale setting means-   21 image pickup apparatus-   22 image sensor-   23 image pickup apparatus main body-   24 image pickup lens-   25 scale-   26 display-   27 image processing apparatus-   28 magnification adjusting movable lens-   29 position sensor-   30 microcomputer

1. A lens exchange type image pickup apparatus having an imageprocessing apparatus of displaying an image of an object picked up by animage sensor and a scale indicative of a reference length injuxtaposition on an image screen of a display, in which an image pickuplens mounted to an image pickup apparatus main body has opticalmagnification outputting means for outputting a predetermined opticalmagnification, and the image processing apparatus includes an actualmagnification calculation means for calculating an actual magnificationon the screen of a display based on the optical magnification, the sizefor the image sensor, and the size of the image screen, and scalesetting means for setting a scale based on the calculated actualmagnification and the reference length of the scale to be displayed. 2.An image pickup apparatus according to claim 1, wherein the opticalmagnification outputting means has a memory device for storing apreviously measured optical magnification.
 3. An image pickup apparatusaccording to claim 1, wherein the image pickup lens, in a case where itis a zoom lens having a magnification adjusting movable lens, has aposition sensor for detecting the position of the movable lens or theposition of a movable portion corresponding thereto, and the opticalmagnification outputting means has a memory device for storing aposition-magnification conversion data for outputting an opticalmagnification in accordance with the detection position of the positionsensor based on the previously measured optical magnification.
 4. Animage pickup lens mounted detachably to an image pickup apparatus mainbody having an image sensor, and including optical magnificationoutputting means for outputting a previously measured opticalmagnification.
 5. An image pickup lens according to claim 4, wherein theoptical magnification outputting means has a memory device for storing apreviously measured optical magnification.
 6. An image pickup lensaccording to claim 4, having a magnification adjusting movable lens forchanging the optical magnification and a position sensor for detecting aposition of the movable lens or a position of a movable portioncorresponding thereto, in which the optical magnification outputtingmeans has a memory device for storing a position-magnificationconversion data for outputting an optical magnification in accordancewith the detection position of the position sensor based on thepreviously measured optical magnification.
 7. An image pickup apparatushaving an image processing apparatus intended for displaying an image ofan object picked up by an image sensor through a magnificationcontrollable image pickup lens and a scale indicative of a referencelength in juxtaposition on a display of a predetermined screen size, inwhich the image pickup lens has a position sensor for detecting aposition of a magnification adjusting movable lens or a position of amovable portion corresponding thereto, and a microcomputer foroutputting an optical magnification and a nominal magnificationcorresponding to the detection position of the position sensor based onthe predetermined position-magnification conversion table, and the imageprocessing apparatus has a scale setter for setting the scale based onan actual magnification and a reference length of the scale to beindicated.
 8. An image pickup lens mounted to an image pickup apparatusmain body intended to display image of an object picked up by an imagesensor and a scale indicative of a reference length in juxtaposition ona display of a predetermined screen size, including a zoom ring foroperating the magnification adjusting movable lens, a click mechanism tostop at a position for the scale marking number of a nominalmagnification corresponding to an actual magnification attached to azoom indicator, a position sensor for detecting a position of amagnification adjusting movable lens or a portion of a movable positioncorresponding thereto, and a microcomputer for outputting an opticalmagnification and a nominal magnification corresponding to the detectionposition of the position sensor based on the previously setposition-magnification conversion table, in which a nominalmagnification data corresponding to a scale marking value indicated tothe zoom indicator is outputted in a case where the detection positionoutputted from the position sensor is within a predetermined range oferror previously set around the click position stopped at the clickmechanism as a center.
 9. An image pickup lens according to claim 8,wherein an optical magnification data corresponding to a position dataset as a click position is outputted in a case where a detectionposition outputted from the position sensor is within a predeterminedrange of error previously set around the click position stopped by theclick mechanism as a center.